1. Field of the Invention
The present invention relates generally to arc lamps, and more specifically to arc lamps of the type which have short arc gaps and integral, internal reflectors.
2. Description of the Prior Art
It is well known to utilize ceramic lamps having short arc gaps to provide compact yet intense sources of light. Such lamps are utilized for example, in medical and industrial endoscopes and for material studies. The lamps can also be used as search lights for outerspace and undersea vehicles. Such lamps include a sealed chamber which contains a gas pressurized to several atmospheres, an anode and cathode mounted along the central axis of the concave chamber to define an arc gap, an integral concave reflector which serves to collimate light generated at the arc gap, and a window at the mouth of the chamber to permit external transmission of the collimated light from the lamp.
There are many applications where it is desirable to obtain the greatest intensity of light as possible. In order to achieve greater light intensity, more power must be applied to the ceramic lamps. The ceramic lamps of the prior art were limited to about one thousand watts and produced a peak beam candle power of three million candellas. Efforts to increase the light intensity by increasing the power resulted in overheating and damage to the lamp. In order to increase the power of the lamps, a way must be found which provides greater cooling.
Xenon lamps have been developed which use water cooling. However, xenon lamps are very fragile making them unsuitable for rugged environments such as in outerspace or undersea. The high pressure xenon lamps are subject to explosion and are very dangerous. In addition, high power xenon lamps are very bulky, usually four inches in diameter by eighteen inches long. An outside reflector must be added around the lamp to direct light and thus further increases the size. Ceramic type arc lamps have an internal reflector and are much more compact in size, but as yet, they have not been water cooled.